One of the niftiest Firefox add-ons to come out of Mozilla Labs is Ubiquity, a natural language commander that adds killer functionality on-page in Firefox. Let's take a closer look.

First, if you haven't already, install the Ubiquity add-on for Firefox. (Mac users, you should also install Growl to get status messages from Ubiquity.) Ubiquity is still pre-1.0, so be prepared for possible hiccups or Firefox slowdowns with Ubiquity installed. While the current 0.1.5 release saw tons of stability improvements over the initial preview, it still is very beta software.

Basic Usage

Once you've got Ubiquity installed, to invoke it, hit Ctrl+Space (Windows) or Option+Space (Mac) from any web page in Firefox and you'll get the Ubiquity command panel. (This action and result will look and feel very familiar to fans of application launchers like Launchy or Quicksilver on the desktop.) From the command panel, you can do things by just starting to type an action related to a web service. Try it: any letter of the alphabet will bring up a list of matching commands in a suggest-as-you-type drop-down.

For example, you can search Amazon by typing am, which will highlight amazon-search, then hit Space and type a word, like Lifehacker. Inside the Ubiquity panel, you'll get your results, as shown.

This works for every search engine you'd expect: Google, Wikipedia, Flickr, Google Image search, eBay. That's fine, but what makes Ubiquity special is that it has access to your personal data, too, like your Google Calendar. For example:

Invoke Ubiquity and type check Tuesday to see what events are on your calendar that day, as shown. (In the screenshot, I'm checking out a specific date—March 2.)

If you're a Gmail user, Ubiquity knows your contact list. To email a link to the web page you're currently looking at, try the email check this out! to adam command, as shown. You'll get a choice of all the people in your contacts list who match the keyword adam. (Note: This feature is either a bit buggy or I'm crazy, because Adam's address should be the first choice in my case but it's not. Hey, Ubiquity is still beta.)

Hit Enter and Ubiquity will open a new tab with a Gmail message all filled in, like this:

This fun just doesn't stop. Check out more screenshots of a few useful Ubiquity commands in action below. Click each thumbnail to enlarge.

GALLERY

Check the weather

Translate a word or phrase

Search Flickr images (kittens!)

Define a word

Look up a word on Wikipedia

Map a location
END

To see all the commands available to you, invoke Ubiquity and enter command-list.

Advanced Usage

Many of the commands you see above you can easily recreate using Firefox's built-in search box or keyword bookmarks. But Ubiquity's real power is in its ability to connect data between different web services inside its command panel. For example, you can translate text from one language to another in-page; email selected text, images, or video clips to a Gmail contact; or Google map a list of addresses from Craigslist all in one spot.

Watch this two-minute screencast to see these three advanced mashups in action in Ubiquity.

If Ubiquity's existing selection of commands doesn't do it for you, you can add your own.

Extend Ubiquity

Even in this early version 0.1.5, Ubiquity's command selection out of the box is impressive, but you can add more, too. Anyone can create commands for Ubiquity, and I did just that by creating a Lifehacker Google search command that scours this site's archives for your keyword in the Ubiquity panel.

Going forward, a community of Ubiquity users and programmers will be posting their commands—which you can subscribe to—to the Ubiquity Herd site.

Pick Your Skin

Finally, like Launchy, Quicksilver, and Firefox itself, Ubiquity is skinnable. Right now there are only three skins available (use the skin-list command to see them), but CSS mavens can edit the custom skin to make Ubiquity look how they like.

Have you spent much time with Ubiquity? What are your most-used commands? Got any tips or tricks to share? Post 'em up in the comments.

Gina Trapani, Lifehacker's founding editor, is loving Ubiquity's Wikipedia command, among many others. Her new weekly feature, Smarterware, will appear every Wednesday on Lifehacker. Subscribe to the Smarterware tag feed to get new installments in your newsreader.